Law enforcement agencies made more than 1 million requests for wireless phone information last year, according to data provided by wireless companies to Sen. Edward J. Markey.

That's leading to the Massachusetts Democrat making a new call for congressional action to make the process more consistent and transparent.

Markey's been investigating the collection of cellphone data since his time in the House. He noted in a press release that major wireless carriers have different standards and requirements for providing information to law enforcement sources.

"We need a 4th amendment for the 21st century. Disclosure of personal information from wireless devices raises significant legal and privacy concerns, particularly for innocent consumers," Markey said in a statement. "That is why I plan to introduce legislation so that Americans can have confidence that their information is protected and standards are in place for the retention and disposal of this sensitive data."

On Monday, Markey outlined what he would envision being included in that legislative proposal:

1. Require regular disclosures from law enforcement on the nature and volume of requests.

2. Curb bulk data information requests such as cell tower dumps that capture information on a large group of mobile phone users at a particular period of time and require that any request be more narrowly tailored, when possible.

3. Require, in the case of emergency circumstances, a signed, sworn statement from law enforcement authorities after receipt of information from a carrier that justifies the need for the emergency access.

4. Mandate creation of rules by the Federal Communications Commission to limit how long wireless carriers can retain consumers' personal information. Right now, no such standards exist.

5. Require location-tracking authorization only with a warrant when there is probable cause to believe it will uncover evidence of a crime. This is the traditional standard for police to search individual homes.